How common are STDs?

Sexually transmitted diseases (STDs) can also be known as sexually transmitted infections (STIs). They are infections that are usually spread from person to person during vaginal, anal, and oral sex.

Many STDs are quite common with the CDC estimating there were 26 million new STDs in 2018 in the United States, with almost half of new STDs among youth aged 15 – 24 years (1).

The most common STDs are chlamydia, gonorrhea, trichomoniasis, and syphilis. Other STDs that we also offer at-home testing for are hepatitis B, hepatitis C, and HIV.

Chlamydia is caused by infection with the bacterium Chlamydia trachomatis.

Over 1.7 million cases of chlamydia were reported to the CDC in 2018, with an increase to over 1.8 million reported cases in 2019. However, actual annual chlamydia cases are estimated to be closer to 2.86 million (1).

50-60% of new chlamydia infections occur in individuals aged between 15 and 24 years. Reported chlamydia rates are approximately two times higher in females compared to males (2). The prevalence of chlamydia varies between racial and ethnic groups, with significantly higher rates among blacks compared to whites (2).

Chlamydia is easily treated with oral antibiotics (3).

Gonorrhea is caused by infection with the bacterium Neisseria gonorrhoeae.

There were 583,405 cases of gonorrhea reported to the CDC in 2018, and 616,392 reported cases in 2019 (1).

50-60% of new gonorrhea infections occur in individuals aged between 15 and 24 years. Reported gonorrhea rates are higher in males than females (2). The prevalence of gonorrhea varies between racial and ethnic groups, with significantly higher rates among blacks compared to whites (2).

Dual antibiotic treatment was previously recommended for gonorrhea infections due to antimicrobial resistance (3). However, due to other health concerns, now only ceftriaxone is recommended for treating gonorrhea in the United States (4).

Trichomoniasis is caused by infection with a protozoan parasite called Trichomonas vaginalis.

As of 2018, there are an estimated 2.6 million individuals with trichomoniasis in the United States (1).

Trichomoniasis prevalence is significantly higher among African American females (9.6-13%), compared to Hispanic (1.4%) and non-Hispanic white females (0.8-1.8%) (5).

Prescription antibiotics are an effective treatment for trichomoniasis (3).

Syphilis is caused by the bacterium Treponema pallidum subspecies pallidum. It has been called “The Great Pretender”, as symptoms can resemble other diseases. If syphilis is untreated it can cause serious health complications.

In 2018, there were 115,045 new syphilis cases reported in the United States. In 2019, this increased to 129,813 reported cases of all stages of syphilis, including 38,992 cases of primary and secondary syphilis, which are the most infectious stages of the disease. In 2019, there were 1,870 reported cases of congenital syphilis (when the fetus acquires syphilis before birth) (1).

Primary, secondary, and early latent stage syphilis (infection within 2 years) is treated with a single intramuscular dose of Benzathine penicillin G. Late latent stage syphilis (more than 2 years after original infection) requires three intramuscular doses of Benzathine penicillin G at weekly intervals (3).

Hepatitis B
Hepatitis refers to inflammation and damage to the liver. The most common causes of hepatitis are three viruses known as hepatitis A, B, and C. The hepatitis B virus is a major global health problem that can cause both acute (short-term) and chronic (long-term) diseases.

Hepatitis B is most prevalent in the western Pacific region and in Africa, where at least 6% of the adult population is infected. In the United States, a total of 3,322 cases of acute hepatitis B were reported to CDC in 2018, but actual estimates were closer to 21,600 (6).

There are no specific treatments for an acute hepatitis B infection with most adults not showing any symptoms and not progressing to chronic infection (7). Medications are available for chronic hepatitis B, but only 10% to 40% of individuals with chronic hepatitis B will require treatment. These medications suppress the replication of the virus, thereby slowing the progression of cirrhosis and reducing the risk of liver cancer, but they generally do not cure an infection, so must continue for life (7).

Prevention is the best option to avoid hepatitis B, as a very effective and safe vaccine is available (7).

Hepatitis C
Hepatitis refers to inflammation and damage to the liver. The most common causes of hepatitis are three viruses known as hepatitis A, B, and C. The hepatitis C virus causes acute (short-term) infections in some individuals, but in most individuals, the virus remains in the body causing serious chronic (long-term) infection.

In 2018, there were 3,621 new cases of hepatitis C reported to the CDC. However, actual estimates are closer to 50,300 new cases during 2018 (8). During 2013-2016, there were an estimated 2.4 million individuals in the United States with chronic hepatitis C (9). In 2018, there were 15,713 US death certificates with HCV recorded as an underlying or contributing cause of death (7), but actual numbers are estimated to be considerably higher (10).

Hepatitis C is treated with antiviral medications to eliminate the virus from the body. Newly developed “direct-acting” antivirals have improved treatment considerably with fewer side effects and shorter treatment periods. Nowadays, over 90% of individuals infected with hepatitis C can be cured with 8-12 weeks of oral therapy (11).

Human immunodeficiency virus (HIV) is a sexually transmitted infection, which occurs by contact or transfer of blood, semen, pre-ejaculate, and vaginal fluids. There are two types of HIV. HIV-1 is the virus that was initially discovered. It is more virulent and infective than HIV-2 and is associated with most of the HIV infections around the world. HIV-2 is not transmitted as easily and is predominantly confined to infections in West Africa (12).

An estimated 38 million individuals worldwide were living with HIV at the end of 2019 (12). In the United States, there were an estimated 1.2 million individuals living with HIV, with approximately 14% being unaware of their HIV status.

Although there is no cure for HIV, effective antiretroviral therapy (ART) ensures that infected individuals can live relatively normal lives and prevents the transmission of HIV.

1.Sexually Transmitted Infections Prevalence, Incidence, and Cost Estimates in the United States. CDC Jan 25 2021
2. Sexually Transmitted Disease Surveillance, 2018. CDC
3. Workowski KA & Bolan GA (2015) Sexually Transmitted Diseases Treatment Guidelines, 2015. MMWR Recomm Rep, 64 (RR-03), 1-137.
4. Gonococcal Infections Among Adolescents and Adults. Sexually Transmitted Infections Treatment Guidelines, 2021. (Reviewed July 2021).CDC.
5. Trichomoniasis Statistics. CDC Feb 27 2020.
6. Viral hepatitis surveillance—United States, 2017. CDC
7. Hepatitis B, World Health Organization. July 2020
8. Viral Hepatitis Surveillance Report 2018 — Hepatitis C. CDC. August 2020
9. Hofmeister MG, et al. (2019) Estimating Prevalence of Hepatitis C Virus Infection in the United States, 2013-2016. Hepatology, 69 (3), 1020-1031.
10. Mahajan R, et al. (2014) Mortality among persons in care with hepatitis C virus infection: The Chronic Hepatitis Cohort Study (CHeCS), 2006-2010. Clin Infect Dis, 58 (8), 1055-1061.
11. Initial Treatment of Adults with HCV Infection. August 2020
12. HIV/AIDS. World Health Organization.

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